Shielding system for vapor-converters.



C. LE G. FORTESCUE. SHIELDING SYSTEM FOR VAPOR CONVERTERS. APPLICATION FILED AuG.9. 1915.'

L3L5@ Mmm .my 3, 1917.

.'llllll WITN ESSES I INVENTOR Char/e5 at? Farescfff u I AToRNE car-IAnLEsmz cf. roRTEscUE, or PITTSBURGH, PENNSYLVANIA, Assauorv To wEs'Tmc- HoUsnnLEcTmc AND MANUFACTURING coMrAnY, .1i-CORPORATION or PENNSYL- vAma.'

meinst.,

To all vwho/m. may concern:

Be it known that I, CHARLES LE G. Foni rescue, a subject of the King of Great Britain, and a resident of Pittsburgh, in the county of Allegheny and Stateof Pennsylvania, have invented a new and useful improvement `in Shielding Systems for` similar evacuated electric apparatus, current is conveyed between the electrodes by a stream of'negative electrons, emitted by the cathode and proceeding to the anode. The stream ofelectrons at the cathode may be excited by any of several well known methods, chief among which are the maintenance of a keep-alive arc to the cathode, the maintenance of the cathode at incandescence,

the impacts of a stream of positive ions thereagainst, land thedmpact of a beam of p ultra-violet light.

If, in its passage from the cathode to an anode, a negative electron collides with a particle of residual gas, the particle is broken up into positive ions and negative electrons, both of which receive an initial impulse toward the anode by the impact. The newly freed negative electron moves on very rapidly because the propelling force of the electrostatic field is substantially coincident in direction with the initial impulse I thus given, but the newly freed positive ion moves but slowly and may soon come to rest and even reverse its direction of movement because ofthe neutralizing inuence of the electrostatic field upon the initial impulse. Furthermore, the acceleration'tending to be imparted to the positive ion by the electrostatic field is much less than that ofthe negative electrons because of the vastly larger mass of the former, although carrying an equal charge. The delivery of a specification of Leaersra'tnt.

orina.

SHIELDING SYSTEM FOR VAPOR-CONVERTERS.

Patented .hay a, rara Application iled August`9, 1915. Serial No. 44,428.

glancing blow t o a gas particle by a negative electron may disrupt the particle and force the-resultant bodies more orless transversely to the arc path intocomparatively Weak accelerated, they may bombard the electrodeso energetically as to break down the negativeelectrode reluctance thereof, causing short circuiting or reverse arcing within.

the apparatus. This harmful action is especially liable to take place if the positive ions impinge upon a globule of mercury or other foreign matter upon the electrode surface. By my invention, I provide means and apparatus whereby these tramp ions are neutralizedand their harmful action prevented.

Referring to the accompanying drawing for a more detailed understanding of my invention, I show a vapor converter of the metal-case type at l, said converter embodying a solid anode 2 and a cathode 3, preferably formed of vaporizable reconstructing material, such, for example, as mercury or suitable amalgams. The anode 2 and the cathode 3 are connected, respectively, to the terminals of. a source of. alternating current 4 through a load 5, and the cathode 3 is maintained in an active position by any suitable means, such, for example, as a keepalive circuit 6. The anode 2 is surrounded and protected by a shielding system similar to that shown and claimed in a copending application of S. W. Farnsworth, Serial No. 445,429, filed Aug. 9, 1915, and assigned to the Westinghouse lectric & Manufacturing Company. Briefly, said shielding systemv embodies a conducting cylindrical casing 7 supporting a pair of transverse perforated .plates 8 and '9. Conducting tubular members 10-10 are mounted in the perforations of the plates 8 and 9, and the two groups ofconducting tubular membersare connected, respectively, to adjustable points in a resistance member 11 connected between the anode 2 and the cathode 3. By suitably adjusting the `points of connection to the resistance member 11, the .tubular niembers 10-10 may be charged to any desired intermediate potential between those of the electrodes. v f

In the operation of my device, when the anode 2 is positive with respect to the cathode 3, a stream of negative electrons proceed from the latter through the tubular members 10-10 to the anode 22. As

above pointed out, at the `instant of reversal.

plication above referred to in that the potential of the suppressor shields may be adjusted Within wide limits and, thus, the -positive space charge may be neutralized Ito any desired degree, as is found'essential in operation.

Throughout this description, I have explained the action of my device in accordance with the theory which seems most plausible in view of the present knowledge of the underlying phenomena. I desire it to be distinctl understood, however, not con ne myself to said theory of operation but merely present the same to aid in an understanding of the inventionf I t While I have shown my invention in its preferred form, skilled in the art that it is susceptible of various minor changes and modications withoutdeparting from the spirit thereof, and 'I desire, therefore, that-only such limitations shall be placed thereupon. as are imposed by the prior art or are specifically set forth in the appended claims.

I claim as my invention:

1. In a vapor converter, the combination with a pairof electrodes, of means for initiating and maintaining an varc therebetween, a conducting member mounted to embrace sai arc, and means for adjusting the potentia? of said member to that of either electro'de or to any intermediate value.-

In a. vapor converter, the combination with a pair of electrodes, of means for initiating and maintaining an arc therebetween,

/a plurality of conducting members arranged reducing arcing that I do` it will be obvious to those tonembracesaid are in succession, and'means for independently adjusting thefrpotential of either conducting member toj-thatof fc'eitherY electrode o r-at anyintermediate'value" p 3. In avaporconverter, thel lQcombniaiaon with a pair ofelectrodeaof lmeans formi#v tiating and .maintaining an arc v-therebebrace said are, and vvmeans for adjusting the potential'of said member tof that'` of: either electrode or at'any intermediate value, -intween, a conducting 4member mounted to ern-r dependently ofthe flow of electronic curj rent therefrom.- A 4 p 4. In avapor.converter,.the combination with' apair of electrodes, of means for in1-v .tiating and maintaining an arcvtherebe tween, a connection including a current-limiting device 'oi'nin said electrodes, a. conducting mem er em racing4 a portion 'of the conducting member to any desired point in said current-limitingdevice.l p

5. In a vapor-converter, thecombination with a pair of electrodes, of means for initiating and maintaining an arc therebetween, a connectlon including a current-limf iting device joining said electrodes, aplu- ',rality of conducting members embracing of tubular conducting members .disposed in the arc path, means for forcing the varc to traverse sald members, and means for connecting any of said conducting members to any desired point in said currentlimiting device.

7. In 'a vapor converter, the combination with a pair of electrodes, of means -Jfor initiating and maintaining an arc therebetween, a connection including a current-limiting device joining said electrodes, a plurality of groups of tubular conducting mem- 'arc path, and means for .connecting said bers, means for forcing Said arc to traverse the members ofeach of said groups -in succession, and means for independently connectin each of said point 1n said current-llmiting device.

In testimony whereof, I` have hereunto subscribed my name this 28th day of July, 1915.

' CHARLES La aron'rnscun oups to any desired 

